Mg3N2 + H2O ====>Mg(OH)2 + NH3? If not, how do I?

Mg3N2 + 6H2O ====> 3Mg(OH)2 + 2NH3

Easy, just have to concentrate a bit. Just check, 3 Mg both sides, 2 N too, 12 H also and finally, 6 O on both sides as well. Good!